Common-law spousal support in Ontario: who pays, how much

TL;DR. In Ontario, common-law spouses can owe — or receive — spousal support, but only after cohabiting continuously for at least three years, or after having (or about to have) a child together. The Spousal Support Advisory Guidelines run the same calculation as for married couples: amount and duration follow the income gap and length of relationship, with kids in the mix changing the formula. The federal Divorce Act does not apply (you were not married), so the case proceeds under Ontario's Family Law Act in the Ontario Court of Justice or Superior Court. You can run your specific numbers in five minutes on the Cairn calculator — no signup.

Why this matters. Most men assume "common-law" means there is no money owed either way. Half the time that is wrong, and the wrong half is expensive — three to seven years of monthly payments at amounts most men have never seen on a paystub. The other half spend months hesitating to claim support they are entitled to. Neither outcome serves anyone.

When does common-law status actually create a spousal-support obligation?

The federal Divorce Act only governs married spouses. For common-law couples in Ontario, the rules sit in section 29 of the Family Law Act (R.S.O. 1990, c. F.3): you are a "spouse" for spousal-support purposes if you have cohabited continuously for at least three years, OR if you are in a relationship of "some permanence" and have a child together (biological or adopted). That second branch is fact-driven — separate apartments, separate finances, but a shared child can still meet it; living together five days a week while one partner keeps another residence often will not.

Once one of those tests is met, the rest of the spousal-support framework — entitlement, the Spousal Support Advisory Guidelines (SSAG), and the federal tax treatment — applies the same as for married couples. The opening question is never "are we common-law" in the abstract; it is "does section 29 catch this relationship for support purposes."

If you are NOT a section 29 spouse, neither party owes spousal support, regardless of how long you lived together or how unequal the incomes were. There is also no property-equalization right under the Family Law Act for common-law couples — that scheme is married-only. Joint-account funds and jointly-held assets get unwound by trust and contract law, not the FLA. The contrast with the married framework is set out in detail in our companion piece on spousal support in Ontario.

What does "entitlement" mean — and which kind applies to you?

Spousal support in Ontario has three classical bases, all of which appear in the Supreme Court of Canada's decision in Bracklow v. Bracklow, [1999] 1 S.C.R. 420. Even though Bracklow was a married-couple case, the entitlement analysis is what the courts apply to common-law claims under the Family Law Act too.

Compensatory. One partner gave up career, income, or earning capacity to take on caregiving or to support the other's career. The classic Ontario fact pattern is one partner taking extended parental leave while the other's salary doubles. The compensatory claim survives long after the relationship ends and tends to push duration toward the upper end of the SSAG range.

Non-compensatory (needs-based). One partner cannot meet basic expenses after separation while the other can. This is the "you cannot suddenly drop someone from a $200K household to a $40K income" intuition the courts codify into a formula.

Contractual. There is an actual cohabitation agreement or other written promise. Common-law couples can and should write one early; we cover what makes one enforceable in the section on separation agreements in Ontario.

Worked example. A man earning $130,000 whose partner earned $85,000 throughout a six-year cohabitation, no kids — weaker compensatory and weaker needs-based claims against him. The same six years with a child and the partner taking parental leave — strong compensatory claim, plus a needs argument while childcare costs run high. Same length of relationship, opposite outcomes. Run the numbers honestly; the SSAG is a range and the entitlement story drives where in the range you land.

How does the SSAG formula actually compute your amount?

The Spousal Support Advisory Guidelines (Department of Justice, 2008, revised 2016) are not law but they are how every Ontario family-law lawyer, mediator, and judge starts the calculation. There are two formulas:

Without-child-support formula — used when there is no concurrent child support order. Amount equals 1.5% to 2% of the gross income difference per year of cohabitation, capped at 50% of the income difference. Duration is 0.5 to 1 year of support per year of cohabitation, with indefinite support after 20 years OR when the "Rule of 65" applies (recipient's age plus years of cohabitation totals at least 65).

With-child-support formula — used when child support is already being paid. The math is more complex because it starts from net disposable income (after taxes, after child support paid) and equalizes it within a 40 to 46 percent range. The intuition: child support has the first call on cash; spousal support comes off what is left.

For a common-law couple with a six-year cohabitation and one child, payor income $130,000, recipient income $50,000 (with $60,000 imputed for child-support purposes during shared parenting) — the with-child-support formula in 2025 generates roughly $700 to $1,400 per month in spousal support, on top of child support, for three to six years. The actual range varies with what is in your two tax returns and how nights with the child are split. The Federal Child Support Tables drive the child-support number; the spousal calculation is layered on top — see how child support is calculated in Ontario.

Run your specific numbers, including the Ontario tax adjustment, on the free Cairn calculator — it runs both formulas plus the federal child-support tables plus the full tax picture in about two minutes.

How is spousal support taxed — and why does the structure matter so much?

Two rules from the Income Tax Act (R.S.C. 1985, c. 1 (5th Supp.)) drive every spousal-support decision worth more than about $20,000:

• Periodic spousal support is deductible to the payor and taxable to the recipient. This is the line-22000-of-the-T1 deduction that most Canadians have never had to look at. A $1,500-per-month payment costs a payor in the 43% combined marginal bracket about $855 after tax, and leaves a recipient in a 25% bracket with about $1,125 in their pocket.
• Lump-sum spousal support is NOT deductible to the payor and NOT taxable to the recipient. A $50,000 lump-sum settlement is the same $50,000 to both sides — no T1 implications. That is why many higher-income payors prefer monthly periodic support (deduction) while many recipients prefer lump-sum (no tax, certainty, no missed payments).

This tax architecture also unlocks a CRA mechanic most men have never heard of: Form T1213, which lets a payor reduce the tax withheld at source so the deduction comes off each paycheque instead of waiting for the annual refund. It is the single most cash-flow-relevant form in the entire spousal-support kit. CRA's official position on what counts as deductible support lives in Income Tax Folio S1-F3-C3.

Child support, by contrast, is not deductible to the payor and not taxable to the recipient — that rule changed in 1997 and applies to every order made since. Do not confuse the two when planning cash flow.

How is a common-law spousal-support case actually run in Ontario?

Married couples can claim spousal support under the federal Divorce Act in the Ontario Superior Court of Justice or, depending on the issue mix, in the Ontario Court of Justice. Common-law couples cannot use the Divorce Act because there is no divorce — so the claim is brought under the Family Law Act, in either the Ontario Court of Justice or the Family Branch of the Superior Court of Justice (the latter when paired with other issues like child support or property contracts).

Three practical implications for common-law spousal-support claims:

1. There is no two-year limitation period for spousal support like the one that can apply to married couples' property claims. A common-law partner can claim spousal support years after separation, though delay tends to hurt the entitlement analysis — courts ask why you waited if you were genuinely in need.

2. No equalization of net family property. A common-law partner cannot use FLA Part I to split the increase in the other's assets over the relationship. The only property remedies are constructive trust, resulting trust, and unjust enrichment — slower, harder to win, and intensely fact-driven.

3. A cohabitation agreement signed before the relationship — or a separation agreement once you split — can lock in what spousal support looks like, including waiving it entirely if both partners want to. See separation agreements in Ontario for what makes one enforceable.

Procedurally, you file Form 8A (Application — General) to start a claim under the Family Law Act in the Superior Court family branch, or Form 8 (General) in the Ontario Court of Justice. The pleadings include the basis for entitlement (compensatory, needs, or contractual), the SSAG calculation with both incomes, and the requested amount and duration. The first court date in most regions is a case conference, not a trial — the place where most spousal-support files actually settle.

The one thing to do this week

Pull your last two years of T1 general tax returns and your two most recent paystubs — and your partner's same documents if you have access — because that is the entire input set for a credible SSAG calculation. Without those, every conversation about money is guessing.

Where Cairn helps next

This article gives you the framework. The free calculator turns it into your specific numbers — what you would actually pay each month, what would hit your account every two weeks. No email. No account.

• Your real Ontario support numbers in two minutes
• The cash-flow comparison with and without a tax adjustment
• A six-page PDF report you can email to yourself
• 14-day money-back promise if you take it further into a paid plan

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